Premenstrual discomfort, menopausal symptoms especially hot flashes, sweating, anxiety One of the ways Black Cohosh can improve circulation and lower blood pressure is by temporarily dilating blood vessels. A popular herb for women, it helps restore healthy menses and soothes irritation and congestion of the cervix, uterus and vagina.  It can help bring on overdue labor and speed up a delayed labor by ripening the cervix and strengthening uterine contractions.  It may be helpful in treating prostate cancer, but that is still undetermined.